In this renewal application, we seek to integrate innovations of frequency-domain photon migration (FDPM) optical tomography within the Siemen's Inveon system for multi-modality optical, PET, and CT small animal imaging. The specific aims of this proposed project are to: The specific aims of this proposed project are to: (1) Adapt FDPM detection and illumination systems into the gantry of the Inveon CT which can be coupled into the Inveon PET for hybrid CT, PET, and NIR optical tomography; (2) Build an animal bed compatible for CT, PET, and NIR tomography which facilitates administration of anesthesia, maintenance of animal temperature, as well as EKG and respiratory gating; (3) Integrate FDPM data acquisition software and Transpire/BCM RTE-based optical tomography algorithms for determination of percent injected dose per gram of tissue (%ID/gm) for comparison to PET values; (4) Optimize and define NIR optical tomography performance with optical phantoms; and (5) Validate NIR optical tomography in the multi-modality imager using unique imaging agents in animal models of cancer. Once a functioning hybrid NIR optical tomography is optimized and performance metrics determined from phantom experiments, we propose to: (1) Co-inject 18F-fluorodeoxy-glucose ([18F]-FDG) and Li-Cor's IRDye800CW labeled to 2-deoxyglucose (IRDye. 800CW-2-deoxyglucose (2DG)) in animals with orthotopic tumors to compare %ID/gm computed from PET and optical tomography; (2) Compare 9-(4-[18F] fluoro-3-hydroxymethylbutyl) guanine ([18F]-FHBG) and optical analogs in animals with tumors stably transfected to express viral thymidine kinase (vTK) to quantify gene expression with PET and optical tomography with Dr. Charles Brunicardi of the Department of Surgery and Dr. Carlos Gonzales of Cyclotope, Inc; (3) Compare %ID/gm of dual labeled agents targeting HER2 in breast cancer, v3 in tumor angiogenesis, and interleukin-11 receptor alpha expressed in osteoblastic bone metastases in animal models; and (4) Quantify uptake of a peptide that (i) is dual-labeled with 64Cu-DOTA and Li-Cor's IRDye800CW and (ii) targets active matrix metalloproteases, MMP-2, and -9 in gated PET, CT, and NIR optical tomography studies of myocardial infarct and of lung cancer in transgenic mice. PUBLIC HEALTH RELEVANCE: The ultimate objective of this work will be to develop a new small animal imaging modality to complement current techniques for quantitative, hybrid studies. The ultimate objective of this work will be to develop a new small animal imaging modality to complement current techniques for quantitative, hybrid studies using optical tomography based upon time-dependent techniques. If successful, the project will produce the first optical tomography platform which can be economically integrated within existing molecular and anatomical imaging modalities.